Finite element analysis of tunnel excavation and ground improvement techniques employing a new constitutive model for shotcrete

Author(s):  
H Schweiger ◽  
B Schädlich ◽  
P Sedighi ◽  
E Saurer ◽  
T Marcher ◽  
...  
Author(s):  
Weijie Jiang ◽  
Jianping Zhao ◽  
Dingyue Chen

A tensile test of buried PE pipe is designed to test the mechanical performance. Then the constitutive model for the PE pipe can be established. The limit load of the PE pipe with local thinning defect can be studied with the method of combining the orthogonal design of experiment and finite element analysis. Then the factors of local thinning defect pipe limit load factors can be analyzed. The results show that the depth of the defect has a great effect on the limit load (internal pressure and bending moment) of PE pipe. The effects that the axial length of the defect and the circumferential length of the defect have on the limit load are not significant.


2014 ◽  
Vol 508 ◽  
pp. 243-248 ◽  
Author(s):  
Jun Peng Li ◽  
Xiao Li ◽  
Dong Qing Zhu

The plane finite element analysis is mostly adopted in soft rock tunnel excavation instead of three-dimensional nonlinear finite element analysis at present, but almost every underground engineering is a spatial nonlinear problem which, in many cases, cannot be simplified into a plane problem. This paper presents a three-dimensional elastic-plastic finite element analysis of incremental variable plastic in soft rock tunnel excavation, through analyzing the tunnel excavation and support, and combining the incremental variable plastic stiffness method into three-dimensional elastic-plastic model in light of the advantage of increment variable stiffness method and the incremental additional load method. Simulation results show that, the three-dimensional elastic-plastic finite element analysis model presented in this paper changes little final deformation under different load release coefficients, together with small support stress.


Author(s):  
Baojiu Lin ◽  
David W. Nicholson

This study concerns the development of a finite element model to support design improvements in elastomeric seals subject to high temperature and pressure, such as in aircraft engines. Existing finite element codes familiar to the authors do not couple thermal and mechanical fields, nor do they implement thermomechanical contact models suitable for highly deformable materials. Recently, the authors have introduced a thermohyperelastic constitutive model for near-incompressible elastomers. In two subsequent studies, using the constitutive model, a method has been introduced for finite element analysis of coupled thermomechanical response, including boundary contributions due to large deformation and variable contact. A new thermomechanical contact model has also been introduced to accommodate the softness of elastomers. The method has been implemented in a special purpose code which concerns a seal compressed into a well. Several computations are used to validate the code. Simulations of a seal in an idealized geometry indicate rapid pressure increase with increasing compression and temperature.


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